The field of the invention regards Radio Frequency IDentification (RFID) transponders. More specifically, the field includes “hybrid” RFID transponders with active and passive functionality and the control of the active and passive functionality of these hybrid RFID transponders.
Radio Frequency IDentification (RFID) is used in various applications in today's commerce. RFID technology involves the use of: (a) relatively small portable RFID transponders or “tags”; (b) RFID readers that detect the presence of these tags when the tags pass into an interrogation zone of the RFID readers; and (c) a network that is accessible to manage and store the detection of the tags passing through the interrogation zones of the readers.
RFID tags comprise an antenna and control logic, and in some instances an internal power source as well. When a tag contains a power source, the tag may be referred to as an active tag. Active tags can announce their presence whether or not they are receiving power within an interrogation zone of an RFID reader. Tags without an internal power source are referred to as passive tags. Passive tags announce their presence when they are in the interrogation zone of an RFID reader because passive tags are powered by the fluctuating electromagnetic field of the RFID reader.
Both passive and active tags acknowledge their presence and provide their unique identity by modulating electromagnetic waves, in various radio frequency bands, back to the RFID reader. These frequency bands can include low frequencies (e.g., 125-134 kHz), high frequencies (e.g., 13.56 MHz) bands, and ultrahigh frequencies (e.g., 915 MHz). The modulated signals broadcast from the tag's antenna acknowledge the tag's presence to any RFID reader within range of receiving the tag's modulated signal.
Active RFID tags may be detected at one-hundred feet or more and may be broadcasting signals that provide information regarding the location of the active RFID tag, contents of the container to which the tag is affixed, and the unique identifier for the tag itself. Modulated signals from passive tags have a much smaller range and can contain much less data. These signals may be detected in an area of three to ten feet from the tag and may provide little if any information to the reader receiving the signal beyond a unique identification of the tag itself.
The RFID reader may be networked with other system components or databases that can be used to record the presence of a tag at a particular place and time. This presence may be used for tracking shipments, confirming receipt, and for reconciling accounts associated with the RFID tag and the particular object to which the tag is affixed.
The readers and tags communicate “over the air” using various standard communication protocols. These communication protocols enable tags to be read by various RFID readers along a supply chain or other product movement chain of handlers.